Jim, that must be what's happening with my drain line. So I suppose the line that runs forward could have one sag in it; then when it makes the left turn to continue over to the windshield pillar there more than likely could be the second one of which you speak. Whatever, I've basically given up on this annoyance and will continue to clean off the dirty water residue that runs down the sides after using the front unit. That's the reason I usually try to just use the rear system. Oh well...
2006 Alpine 36' FDTS